6 Verification and Calibration
Verification Procedure
Voltage Programming and Readback Accuracy
This test verifies that the voltage programming and measurement functions are within specifications.
Step 1. Turn off the unit under test. Only connect the DMM to the sense screws (see
Test Setup
A). Do
NOT connect the load unit.
Step 2. Turn on the unit under test and program the instrument settings as described in the test record
form under "Voltage Programming & Readback, Min Voltage". Turn the output on. The output status
should be "CV", with the output current close to zero.
Step 3. Record the output voltage reading from the DMM (Vout) and the voltage measured by the
instrument over the interface. The readings should be within the limits specified in the test record form
for the appropriate model under "Voltage Programming & Readback, Minimum Voltage".
The next step applies the full output voltage of the unit under test to the output.
Step 4. Program the instrument settings as described in the test record form under "Voltage
Programming & Readback, High Voltage".
Step 5. Record the output voltage reading from the DMM (Vout) and the voltage measured by the
instrument over the interface. The readings should be within the limits specified in the test record form
for the appropriate model under "Voltage Programming & Readback, High Voltage".
Constant Voltage Load Effect
This test measures the change in voltage resulting from a change in current from full load to no load.
Step 1. Turn off the unit under test. Connect the DMM to the sense screws and connect the load unit.
Make sure that the voltage rating of the load unit matches the voltage rating of the unit under test.
(see
Test Setup
A).
Step 2. Turn on the unit under test and program the instrument settings as described in the test record
form under "CV Load Effect". Turn the output on.
Step 3. Set the load unit for the output current as described in the test record form under "CV Load
Effect". Turn the output on. The output status of the unit under test should be "CV". If it isn't, adjust the
load so that the output current drops slightly.
Step 4. Record the output voltage reading from the DMM.
Step 5. Turn off the output of the load unit. Record the voltage reading from the DMM again. The
difference between the DMM readings in steps 4 and 5 is the load effect, which should not exceed the
value listed in the test record form for the appropriate model under "CV Load Effect".
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